Health officials grappling with the Zika virus in Florida face a mystery: a pregnant woman who set off the Zika scare is not connected to a one square-mile area in where officials have identified the virus.

Mosquito control officials have twice been to the home of a Palm Beach County resident with a non-travel case of Zika virus and believe there is “very, very low potential” the person was infected locally or has passed on the virus to mosquitoes in the neighborhood.

Florida epidemiologists have ruled out travel as a possible source for two Zika infections — one in Miami-Dade and one in Broward — suspected of being the nation’s first cases transmitted by local mosquitoes, State Surgeon General Celeste Philip said Tuesday during a meeting with Gov. Rick Scott and health officials.